2-Chlorophenylhydrazine hydrochloride → HCID 59633025, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 4-(5-bromo-thiophen-2-yl)-2,4-dioxo-butyric acid methyl ester (15 g, 50 mmol) and 2-chlorophenylhydrazine hydrochloride (10.75 g, 60 mmol) in dry MeOH (200 mL) was heated to reflux for 6 h. After cooling to 20° C., a white solid precipitated and was collected by filtration, washed with a small volume of cold MeOH and dried under high vacuum to afford 5-(5-bromo-thiophen-2-yl)-1-(2-chloro-phenyl)-1H-pyrazole-3-carboxylic acid methyl ester (20 g, 100%). 1H-NMR (CDCl3): δ 7.48-7.55 (m, 3H), 7.43 (m, 1H), 7.11 (s, 1H), 6.90 (d, 2H), 6.65 (s, 1H), 3.95 (s, 3H).

Provenance & Evidence